Using the Parallel Port Control Lines

[porto99]

I can use the 8 data lines of this port OK, but when it comes to using the other 4 output lines on the control section of the port I have no luck.

I keep getting 0x0C back when I read thses lines (no matter what I set it to):-

Note Using PortTalk for Windows 2000:

Code:
int ReadPortLPT1C(void)
{
int value = inportb(0x37a);
return value;

}

void WritePortLPT1C(int newData)
{
outp(0x37a, newData);
}

As I said it works fine for the data lines (8) at address 0x0378.

 

[LyMc]

The four control lines are not meant to be "read" in the sense that data lines are. Some of them are meant to be read by the port driver and some written to. There are many places on the web that detail how to program parallel ports; see, for instance,

http://www.epanorama.net/circuits/parallel_output.html

.